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Title: Internal transport barrier triggered by non-linear lower hybrid wave deposition under condition of beam-driven toroidal rotation

By using gyro-Landau fluid transport model (GLF23), time-dependent integrated modeling is carried out using TRANSP to explore the dynamic process of internal transport barrier (ITB) formation in the neutral beam heating discharges. When the current profile is controlled by LHCD (lower hybrid current drive), with appropriate neutral beam injection, the nonlinear interplay between the transport determined gradients in the plasma temperature (T{sub i,e}) and toroidal velocity (V{sub ϕ}) and the E×B flow shear (including q-profile) produces transport bifurcations, generating spontaneously a stepwise growing ITB. In the discharge, the constraints imposed by the wave propagation condition causes interplay of the LH driven current distribution with the plasma configuration modification, which constitutes non-linearity in the LH wave deposition. The non-linear effects cause bifurcation in LHCD, generating two distinct quasi-stationary reversed magnetic shear configurations. The change of current profile during the transition period between the two quasi-stationary states results in increase of the E×B shearing flow arising from toroidal rotation. The turbulence transport suppression by sheared E×B flow during the ITB development is analysed, and the temporal evolution of some parameters characterized the plasma confinement is examined. Ample evidence shows that onset of the ITB development is correlated with the enhancement of E×Bmore » shearing rate caused by the bifurcation in LHCD. It is suggested that the ITB triggering is associated with the non-linear effects of the LH power deposition.« less
Authors:
 [1] ;  [2]
  1. Southwestern Institute of Physics, Chengdu 610041 (China)
  2. Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
Publication Date:
OSTI Identifier:
22408208
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 3; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; BEAM INJECTION; BEAMS; BIFURCATION; ELECTRIC FIELDS; ELECTRON TEMPERATURE; ION TEMPERATURE; LANDAU DAMPING; LIMITING VALUES; LOWER HYBRID CURRENT DRIVE; MAGNETIC FIELD CONFIGURATIONS; NONLINEAR PROBLEMS; PLASMA CONFINEMENT; REVERSED SHEAR; SHEAR; TIME DEPENDENCE; TRANSPORT THEORY; TURBULENCE; WAVE PROPAGATION